Hitherto, inorganic insulation films of silicon dioxide or the like prepared by chemical vapor deposition method or the like have been used as layer insulation films for semiconductors. However, inorganic insulation films of silicon dioxide or the like are high in dielectric constant, and use of organic materials is being investigated as insulation films for the purposes of speeding up and higher performance. As organic materials for semiconductors, there are used polyimide resins which are superior in heat resistance, electrical characteristics and mechanical characteristics. With recent enhancement in function and performance of semiconductors, further remarkable improvement in heat resistance, electrical characteristics, moisture-absorption characteristics, and thermal expansion coefficient is demanded, and thus, resins of further higher performances are needed.
Under the circumstances, it has been attempted to use polybenzoxazole resins which are superior to polyimide resins in water absorption and electrical characteristics, as insulation materials for semiconductors. It is easy for polybenzoxazole resins to satisfy only one of thermal characteristics, electrical characteristics, mechanical characteristics and physical characteristics. For example, a polybenzoxazole resin comprising 4,4'-diamino-3,3'-dihydroxybiphenyl and terephthalic acid has much superior heat resistance such as high heat decomposition resistance or high Tg, but is not so good in electrical characteristics such as dielectric constant and dielectric loss tangent. A polybenzoxazole resin comprising 2,2'-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and terephthalic acid shows good electrical characteristics such as low dielectric constant, but is not so good in heat resistance and physical characteristics. Thus, at present, there are obtained no resins which are excellent in all of thermal characteristics, electrical characteristics, mechanical characteristics and physical characteristics.